Protozoa infections are a worldwide health problem that preferentially affects populations in underdeveloped countries. Plasmodium, Leishmania, Trypanosoma, Toxoplasma, Neospora, Entamoeba and Trichomonas are some of the most important genuses of protozoan parasites that infect and invade cells, tissues and organs. These parasites proliferate, migrate and mutate to evade the chemotherapeutic effects of drugs that were previously effective for their treatment. The use of metals and metals complexes to control and treat these parasites, seems a very prominent alternative. Palladium, platinum, ruthenium, antimonium, gold, iron and vanadium are some of the metals that have been evaluated as antiprotozoal treatments with favorable results. A review of the experimental effects of metal complexes on these parasites follows, along with commentary.